1,3-Propanediol or its reactive derivatives are useful in many applications, for example as chemical intermediates and as monomers for polyesters and other types of condensation polymers. However, the uses of these compounds have been retarded by the relative difficulty, and hence high cost, of making them. Thus, improved, lower cost methods of making such compounds are desired.
The "Prins" reaction has been known for a long time to make 1,3-diols. In this reaction an olefin is often reacted with formaldehyde (or another aldehyde) to form a 1,3-diol (or its mono- or diester if a carboxylic acid is present) or a cyclic ether of some sort, in the presence of a strong Bronsted or Lewis acid, although oftentimes there are large amounts of byproducts, see for instance B. B. Snyder in B. Trost, et al., Ed., Comprehensive Organic Synthesis, Vol. 2, Pergamon Press, Oxford, 1991, p. 527-534, and D. R. Adams, et al., Synthesis, 1977, p. 661-672. Selectivity in the Prins reaction is sometimes difficult, due to the large variety of possible products. In order to make 1,3-propanediol or its derivatives it would be necessary to use ethylene as the olefin, and it is well known that ethylene does not react well in the Prins reaction, see for instance, Japanese Patent Applications 51-143,606 and 51-143,605 which describe the preparation of 1,3-propanediols and its esters from ethylene, formaldehyde and carboxylic acid, using a Bronsted acid catalyst.
What are needed are processes for manufacturing diesters of 1,3-propanediol which do not have the deficiencies of the prior art. Other objects and advantages of the present invention will become apparent to those skilled in the art upon reference to the detailed description which hereinafter follows.